Valve for gas compressors and pumps.



A. J. WEST. VALVE FOR GAS OOMPRESSORS AND PUMPS.

APPLICATION FILED JULY 12, 1911.

Patented Feb. 11, 1913.

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ARTHUR J. WEST, OF BETHLEHEM, PENNSYLVANIA.

VALVE FOB GAS COMPBESSORS AND PUMPS.

Specification of Letters Patent.

Application filed July 12, 1911.

Patented Feb. 11,1913. Serial No. 638,132.

To all whom it may concern:

Be it known that I, ARTHUR J. WEST, a citizen of the United States, residing at Bethlehem, in the county of Northampton and State of Pennsylvania, have invented certain new and useful Improvements in Valves for Gas Compressors and Pumps, of which the following is a specification.

This invention relates to discharge valves for air or other gas compressors, and particularly to a valve of the combined mechanically operated and automatic type. In such valves the valve member proper is moved to its closing position by a positively o erated plunger directly or through the me ium of an interposed air cushion. The valve is subsequently released by the plunger so' as to be permitted to open when the total outward pressure predominates suficiently over the inward pressure to overcome the friction and inertia of the valve. These are often great enough to require an undue predomination of such pressure resulting in a deranged valve ac-- tion and a consequent loss of efliciency. In a co-pending application filed July 12, 1911, Serial No. 638,133, I have described a mechanism in which this diiliculty' is overcome by causing the plunger to exert a retractile force upon the automatic or floating valve.

The purpose of the present invention is to secure a similar result by a difi'erent means, consisting essentiall in a construction in which the area of t e floating valve subjected to cylinder pressure acting in an openin direction is made greater than the area 0 that valve exposed to discharge pressure acting in a closing direction, and an area equal to the difierence between the above named areas is exposed to atmospheric ressure acting in a closing direction. Thus t e opening tendency during the discharge stroke is increased so as to overcome friction and inertia.

The invention will be described in connection with the accompanying drawing, in which:

Figure 1 is a vertical section throu h a discharge valve showin the valve rea y to open; and Fig. 2 is a similar view showing the position assumed by the parts when the valve has opened.

' 1n the drawings, 1 represents the walls of the cylinder head and 2 the discharge passage formed in the cylinder head.

3 indicates a point within the cylinder.

4 is the valve operating rock shaft which ma be rocked in any suitable manner. The roc shaft carries the usual rocker arm 5 connected by a :link '6 to the plunger 7. This plunger is guided in a'bonnet 8 held by studs and nuts 9 to the cylinder head. The studs 9 also pass through a flange on the valve cage 10, which is closely fitted in suitable openings in the cylinder head walls and is provided with a series of ports 11 and 12, as clearly shown in the fi res.

The floating valve 13 slides in t e valve ca e 10. It is of the piston type and is provi ed with a metallic packing ring 14 so that in the closed ositlon of theyalve, as shown in Fig. 1, a tight joint is made. This floating valve 13 consists of an im erforate head 15 having two coaxial cylin rical extensions or shells 16 and 17 attached thereto. The outer shell 16 is provided with ports 18 for a purpose later to be described, and is provided at its end with a rim or flange 19. The bore of the cage 10 is of two diameters, the smaller of which is closely fitted b the main walls of the shell 16, while the ange 19 makes a close fit in the larger bore. From this results the formation ofa pocket 20, in which, in the closed position of the valve, air is. trapped to form a cushion andv brin the valve quietly to rest. The plunger 7 1s tubular in form and open at its outer end while at its inner end it carries an annular head 21 closely fitting in the annular space between the shells 16 and 17-, a tight joint being made with each 05 said shells by means of the packing rings 22 and 23.

Considering. the valve in the position shown in Fig. 1, it will beseen "that the floating valve 13 is subject to pressure within the cylinder over its entire head 15, such pressure acting in the opening direction. In opposition to this opening'pressure it is acted upon by atmospheric pressure over the entire'a-rea withinthe cylindrical shell 17, while the annular area outside of the shell 17 is subject 'to discharge pipe pressure entering through the ports 18. By

varying the relative areas within the shell 17 and the annular area outside such shell the valve may be given any desirable opening tendency. The ports 18 are placed at some distance from the head end of the valve so as to be overtraveled by the head 21 of the plunger 7, thus creating an air pocket or cushion which will prevent actual physical contact between the head of the plunger 7 and the floating valve.

With this statement of the construction, the operation of the valve can now be traced out. Assuming the valve to be in the pos1- tion of Fig. 1, the piston of the pump will be moving toward the right. The lunger 7 is shown as near the right hand imit of its motion. The opening pressure exerted upon the valve will increase until it is suficient to preponderate over the closing pressure and the friction and inertia of the valve. Knowing the discharge pressure and the other characteristics of the pump this may be readily proportioned so that the valve will 0 en ports 11 when the ressure in the cylin er is substantially equa to the discharge pressure. Assuming such preponderance to be attained the valve 13 will quickly move to the position shown in Fi 2, being gently brought to rest by the air cushion between the plunger and valve. By the time that the piston of the pump has reached the end of its stroke to the right the rock shaft 4 and its connected mechanism will have moved the plunger 7 to the left thus forcing valve 13 through the medium of the air cushion interposed between the plunger and valve to its ,closed position, or if the pressure in the cylinder should fall prior to such movement of the plunger 7 the valve 13 would automatically close. In either event the closing movement of the valve is checked and cushioned by the air pocketed in-the space 20. At the time the plunger 7 again moves toward the right the pressure in the cylinder will be so low that the valve 13 will be held closed by discharge pipe pressure, thus allowing the plunger 7 to move to its right hand position, leaving the valve 13 closed. This cycle of operations is repeated for each double stroke of the pump piston.

It is obvious that by varying the ratios between the areas exposed to cylinder, discharge and atmospheric pressures, the valve may be caused to open either before,'simu taneously with, or after the equalization of cylinder and discharge pressures, as conditions may require.

Having thus described the invention, what I claim is 1. In a discharge valve for gas pumps, the combination of a valve of the piston t pe adapted to be urged in its opening direction by pressure within the pump and in its closing direction by ressure acting over a part of its area assisted by a less pressure acting over the remainder of its area; and a plunger adapted to move the valve to its closed posit-i0 r 2. In a discharge valve for gas pumps, the combination of a valve of the piston t pe adapted to be urged in its opening direction by pressure within the pump and in its closing direction by pressure acting over a part of its area assisted by a less pressure acting over the remainder of its area; an air cushion to check the closing movement of the valve; and a plunger adapted to rhove the valve to its closed position.

3. In a discharge valve for gas pumps, the combination of a valve of the piston type adapted to he urged in an opening direction by ressure within the pump and in a closing irection by discharge pressure acting over a portion of its area assisted by a less pressure acting over the remainder of its area; and a plunger adapted. to move the valve to a closed position by the medium of an interposed air cushion.

4. In a discharge valve for gas pumps, the combination of a valve adapted to be urged in its opening direction by pressure within the pump and in its closing direction by discharge pressure acting over a part of its area assisted by a less pressure acting over the remainder of its area; and a plunger adapted to move the valve to its closed position.

5. In a discharge valve for gas pumps, the combination of a valve adapted to be urged in an opening direction by pressure within the pump and in a closing direction by discharge pressure acting overa portion of its area assisted by a less pressure acting overthe remainder of its area; and a p nger adapted to move the valve to a closed position by the medium of an interposed air cushion.

6. In a discharge valve for gas pumps, the combination of a valve subject to pressure within the pump and consisting of a head having two cylindrical shells attached thereto, the outer'shell having ports whereby the annular space between the shells is subject -to discharge pressure; a cylindrical plun er adapted to act as a piston in the annu lar space between the shells, such plunger being so formed as to permit atmospheric pressure to act against the valve within the inner shell; and means for actuating the plunger to alternately close and release the valve.

7.111 a discharge valve for gas pumps having a discharge passage, the combination of a ported valve cage mounted to communicate with the pump and with the discharge passage; a piston valve movably mounted in the valve cage and consisting of a head portion and two coaxial cylindrical shells attached thereto, the outer shell having ports whereby the annular space between the shells is subject to discharge pressure; a plunger adapted to act as a piston in the annular space between the shells, such plunger permitting communication between the atmosphere and theportion of the valve within the inner shell; and means for actuating the plunger to alternately close and release the valve.

8. In a discharge valve for gas pumps having a discharge passage, the combination of a ported valve cage mounted to communicate with the pump and with the discharge passage; a piston valve movably mounted in the valve cage and consisting of a head portion and two coaxial cylindrical shells attached thereto, the outer shell having ports whereby the annular space between the shells is subject to discharge pressure; an air cushion adapted to check the closing movement of the valve; a plunger adapted to act as a piston in the annular space between the shells, such plunger permitting communication between the atmosphere and the portion of the valve within the inner shell; and means for actuating the plunger to alternately close and release the valve. I

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ARTHUR J. WEST.

Witnesses B. A. BRENNAN, J. E. PICKARD. 

